The present invention relates to a braked knee joint having a thigh part and a lower leg part which are provided with braking surfaces which are adapted to one another and which, because of the moving capacity of the thigh part relative to the lower leg part, are pressed against one another during loading. The braking surfaces essentially have a contour which is circular in vertical section and has a constant radius relative to the axis of rotation. The braked knee joint also has a stop for limiting the extending movement of the knee joint out of the flexed position.
A braked knee joint of this general type is known, for example, from Austrian Pat. No. 243,431. When the knee joint is loaded, for example, when walking, the braking surfaces press heavily against one another and, because of the frictional force which exists between them, they brake the movement of the knee joint. When the knee joint is fully loaded in the extended position, the braking surfaces virtually provide an arresting effect which is released only by relieving the load on the joint.
In a braked knee joint of this type, the lower leg, when the load is relieved, can virtually swing freely relative to the thigh, because the braking surfaces produce practically no frictional force. When the thigh is brought forward during the walking action, the lower leg, assisted by an advancing spring, follows in a swinging movement until the leg is extended. This forward swinging movement of the lower leg is limited by a stop. Despite greater efforts in the designing of the stop, success has not been achieved in constructing a stop which leads to a gentle stop movement for all applications in which the forward swinging of the lower leg part takes place with a more or less large swing. Heretofore, a jerky, abrupt termination of the forward swinging movement could therefore not be avoided.